The present invention relates to sliding vane pumps. More particularly, the invention relates to a moderately high pressure sliding vane pump having a non-metallic housing.
For the reliable delivery of moderately high pressure fluids at modest cost, the sliding vane pump is the standard of industry. Having relatively few moving parts, the machine will continuously deliver a spectrum of fluids from water to oil up to 250 psi for long operational periods.
Traditionally, many sliding vane pump housings are finish machined from forged or cast brass or stainless steel. The brass alloy for these blanks includes 1% to 2% lead to reduce machine tool fouling and improve forgability. However, when these leaded brass pump housings are used to move potable water, over time lead will leach from the brass alloy into the water. Although the leaching rate is not great, it is nevertheless measurable and by some, considered intolerable for potable fluid use.
In a relative sense, sliding vane pump housings are simple and may be formed from numerous soft castable materials such as high density polymers. U.S. Pat. No. 4,543,228 to D. J. Bingler is representative of a molded plastic housing for a sliding vane pump. The Bingler plastic housing design is also typical in that the Bingler design translates the prior art brass housing configuration directly into the plastic housing configuration. Unfortunately, the plastic modulus of elasticity, G, approximately 1.5 to 2.0.times.10.sup.6 lb./in.sup.2 is considerably less than the leaded brass modulus of about 15.0.times.10.sup.6 lb./in.sup.2. As a consequence, the plastic housing perimeter tends to expand more under the same pressure as compared to brass thereby inducing considerably more leakage and flow loss. The resulting plastic housed pump must be pressure derated considerably and the efficiency suffers from the flow loss.
It is an object of the present invention, therefore, to provide an efficient sliding vane pump having a non-metallic housing.
Another object of the invention is a relatively high pressure pump having a plastic housing.
Yet another object of the invention is a sliding vane pump that will not leach heavy metals into potable fluids.
A still further object of the invention is a connector system for conduits to a polymer pump boss having no threads.
Still another object of the invention is a non-metallic connector system for securing fluid carrier conduits to a nonmetallic pump boss having no threads.